Drive system for a surface treatment apparatus and a surface treatment apparatus having the same

CROSS-REFERENCE TO RELATED APPLICATIONS

0001The present application claims the benefit of U.S. Provisional Application Ser. No. 62/851,811 filed on May 23, 2019, entitled Surface Cleaning Head with Magnetic Gears, which is fully incorporated herein by reference.

TECHNICAL FIELD

0002The present disclosure is generally related to surface treatment devices and more specifically related to a drive system for one or more components of a surface treatment device.

BACKGROUND INFORMATION

0003Powered devices, such as vacuum cleaners, have multiple components that each receive electrical power from one or more power sources (e.g., one or more batteries or electrical mains). For example, a vacuum cleaner may include a suction motor, a debris collector, and a surface cleaning head. The suction motor is fluidly coupled to both the debris collector and the surface cleaning head such that the suction motor can cause a suction force to be generated at the surface cleaning head. The generated suction force urges debris deposited on a surface to be cleaned (e.g., a floor) into entrainment with air passing through the surface cleaning head such that the debris can be deposited in the debris collector. In some instances, the debris collector may be configured to generate one or more cyclones therein such that at least a portion of the entrained debris can be separated from the airflow through cyclonic action.

0004The surface cleaning head may include one or more agitators (e.g., brush rolls) configured to engage the surface to be cleaned. The engagement between the surface to be cleaned and the agitators may dislodge debris from the surface to be cleaned such that the dislodged debris may become entrained within air flowing into the surface cleaning head. In some instances, the surface cleaning head may include additional components (e.g., one or more lights to illuminate an area to be cleaned).

0005The one or more agitators may extend within a suction chamber defined within the surface cleaning head. The suction chamber defines a cavity having an open end through which at least a portion of the one or more agitators extends. A separation distance between the open end and the surface to be cleaned impacts a suction force generated by the suction motor at the open end. As the separation distance increases, a suction force decreases, which may reduce a quantity of debris entrained within air flowing through the surface cleaning head. As the separation distance decreases, the suction force increases. If the separation distance is decreased too much, the suction motor could be damaged.

0006In some instances, the surface cleaning head may include one or more of the debris collector and/or suction motor. In other instances, the debris collector and suction motor may be separate from the surface cleaning head. For example, an upright section (e.g., a wand) may be pivotally coupled to the surface cleaning head and the suction motor and debris collector may be coupled to the upright section. By way of further example, the vacuum cleaner may include a moveable canister fluidly coupled to the surface cleaning head, wherein a flexible hose extends between the moveable canister and the surface cleaning head. The moveable canister can include the suction motor and the debris collector.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages will be better understood by reading the following detailed description, taken together with the drawings, wherein:

<figref idref="DRAWINGS">FIG. <b>1</b></figref> shows a schematic example of a surface treatment apparatus, consistent with embodiments of the present disclosure.

<figref idref="DRAWINGS">FIG. <b>2</b></figref> shows a schematic example of a drive system capable of being used with the surface treatment apparatus of <figref idref="DRAWINGS">FIG. <b>1</b></figref>, consistent with embodiments of the present disclosure.

<figref idref="DRAWINGS">FIG. <b>3</b></figref> shows a schematic example of the drive system of <figref idref="DRAWINGS">FIG. <b>2</b></figref> coupled to corresponding agitators, consistent with embodiments of the present disclosure.

<figref idref="DRAWINGS">FIG. <b>4</b></figref> shows a perspective view of a surface cleaning head, consistent with embodiments of the present disclosure.

<figref idref="DRAWINGS">FIG. <b>5</b></figref> shows a top view of the surface cleaning head of <figref idref="DRAWINGS">FIG. <b>4</b></figref>, consistent with embodiments of the present disclosure.

<figref idref="DRAWINGS">FIG. <b>6</b></figref> shows a side view of the surface cleaning head of <figref idref="DRAWINGS">FIG. <b>4</b></figref>, consistent with embodiments of the present disclosure.

<figref idref="DRAWINGS">FIG. <b>7</b></figref> shows a schematic example of a robotic surface treatment apparatus, consistent with embodiments of the present disclosure.

DETAILED DESCRIPTION

0015The present disclosure is generally directed to a surface treatment apparatus. The surface treatment apparatus includes a surface cleaning head having a first agitator and a second agitator, a rotation of the first agitator causing a corresponding rotation in the second agitator. A drive system is configured to transfer rotational movement from the first agitator to the second agitator such that the first and second agitators rotate concurrently. The drive system includes at least a first ring of magnets and a second ring of magnets, each configured to be rotated in response to the rotation of the first agitator. The magnets are arranged according to polarity in an alternating fashion. The first and second magnet rings may be oriented such that magnetic fields generated by the magnets of each ring interact to cause the first and second magnet rings to rotate together. As such, the first and second magnet rings may generally be described as magnetic gears, wherein the magnetic fields define the cogs (or teeth) of the magnetic gears.

0016<figref idref="DRAWINGS">FIG. <b>1</b></figref> shows a schematic example of a surface treatment apparatus <b>100</b>. As shown, the surface treatment apparatus <b>100</b> includes a surface cleaning head <b>102</b>, an upright section <b>104</b> pivotally coupled to the surface cleaning head <b>102</b>, and a vacuum assembly <b>106</b> coupled to the upright section <b>104</b>. The vacuum assembly <b>106</b> includes a suction motor <b>108</b> and a debris collector <b>110</b>. The suction motor <b>108</b> is configured to cause air to flow along an airflow path <b>112</b> that extends from the surface cleaning head <b>102</b>, into the debris collector <b>110</b>, and through the suction motor <b>108</b>. In other words, the suction motor <b>108</b> is fluidly coupled to both the debris collector <b>110</b> and the surface cleaning head <b>102</b>.

0017The surface cleaning head <b>102</b> includes a first agitator <b>114</b> and a second agitator <b>116</b>. The first and second agitators <b>114</b> and <b>116</b> extend within a suction chamber <b>118</b> of the surface cleaning head <b>102</b>. As shown, the suction chamber <b>118</b> defines a cavity <b>120</b> having at least one open end <b>122</b>, wherein at least a portion of the first and second agitator <b>114</b> and <b>116</b> extend from the open end <b>122</b> and engage a surface to be cleaned <b>124</b> (e.g., a floor). The first and second agitator <b>114</b> and <b>116</b> can be configured to rotate concurrently at the same or different rotational speeds and in the same or different rotational directions. The rotation of the first and second agitators may cause at least a portion of debris adhered to the surface to be cleaned <b>124</b> to be dislodged therefrom. The dislodged debris may become entrained within air flow along the airflow path <b>112</b>. For example, the first and second agitators <b>114</b> and <b>122</b> can be configured to be counter rotating such that dislodged debris is urged towards a central portion of the open end <b>122</b>. In some instances, the airflow path <b>112</b> can extend through an inter-agitator passageway <b>123</b> defined between the first and second agitators <b>114</b> and <b>116</b>. At least a portion of one or more of the first and/or second agitators <b>114</b> and/or <b>116</b> may be substantially isolated from the airflow path <b>112</b> such air flowing along the airflow path <b>112</b> is not incident on the isolated portion of the first and/or second agitators <b>114</b> and/or <b>116</b>.

0018The first and second agitators <b>114</b> and <b>116</b> may include one or more cleaning elements such as bristles (e.g., bristle tufts or bristle strips), fabrics, and/or continuous flexible flaps extending along a body thereof. The cleaning elements may be arranged according to a pattern (e.g., a spiral or chevron pattern). The first and second agitators <b>114</b> and <b>116</b> may have the same or different construction. For example, the one or more cleaning elements of the first agitator <b>114</b> may be stiffer (less flexible) than the one or more cleaning elements of the second agitator <b>116</b>. In some instances, one or more of the first and/or second agitators <b>114</b> and/or <b>116</b> may be removable from the surface cleaning head <b>102</b> (e.g., for cleaning or replacement). For example, the first and/or second agitators <b>114</b> and/or <b>116</b> may be removable from the surface cleaning head <b>102</b> through an openable door.

0019In some instances, at least a portion of the second agitator <b>116</b> can be the forward most portion of the surface cleaning head <b>102</b>. In these instances, the second agitator <b>116</b> can engage a surface (e.g., a wall) that extends from the surface to be cleaned <b>124</b>. Additionally, or alternatively, the cleaning elements of the second agitator <b>116</b> may be configured such that at least a partial seal is formed between the second agitator <b>116</b> and the surface to be cleaned <b>124</b>. Such a configuration may increase a suction force at the open end <b>122</b> by reducing an area through which air may enter the open end <b>122</b>.

0020A second agitator diameter <b>126</b> may measure differently from (e.g., less than) a first agitator diameter <b>128</b>. When the second agitator <b>116</b> is the forward most portion of the surface cleaning head <b>102</b>, such a configuration may improve cleaning performance adjacent a wall. Further, such a configuration, may reduce an overall size of a forward portion of the surface cleaning head <b>102</b>, which may allow at least the forward portion of the surface cleaning head <b>102</b> to extend under an obstacle (e.g., a piece of furniture). A ratio of the second agitator diameter <b>126</b> to the first agitator diameter <b>128</b> (i.e., the second agitator diameter <b>126</b> divided by the first agitator diameter <b>128</b>) may be in a range of, for example, ¼ to 1/1. By way of further example, the ratio of the second agitator diameter <b>126</b> to the first agitator diameter <b>128</b> may be ½. By way of still further example, the ratio of the second agitator diameter <b>126</b> to the first agitator diameter <b>128</b> may be ¾. In some instances, the second agitator diameter <b>126</b> may measure the same as the first agitator diameter <b>128</b>.

0021A first agitator extension distance <b>130</b> and a second agitator extension distance <b>132</b> may measure the same or different. The first agitator extension distance <b>130</b> corresponds to a portion of the first agitator <b>114</b> extending from the open end <b>122</b> towards the surface to be cleaned <b>124</b> (or a direction away from the surface clean head <b>102</b>) and the second agitator extension distance <b>132</b> corresponds to a portion of the second agitator <b>116</b> extending from the open end <b>122</b> towards the surface to be cleaned <b>124</b> (or a direction away from the surface clean head <b>102</b>). The first and second agitator extension distances <b>130</b> and <b>132</b> correspond to the extension distance of the first and second agitators <b>114</b> and <b>116</b> in a non-compressed state. The second agitator extension distance <b>132</b> may measure, for example, greater than the first agitator extension distance <b>130</b>. In this example, when engaging the surface to be cleaned <b>124</b>, the cleaning elements of the second agitator <b>116</b> may be compressed to a greater extent than the cleaning elements of the first agitator <b>114</b>. By way of further example, the first agitator extension distance <b>130</b> may measure greater than the second agitator extension distance <b>132</b>. In this example, when engaging the surface to be cleaned <b>124</b>, the cleaning elements of the first agitator <b>114</b> may be compressed to a greater extent than the cleaning elements of the second agitator <b>116</b>. Additionally, or alternatively, one or more of the first and/or second agitators <b>114</b> and <b>116</b> may be configured to float relative to a body <b>134</b> of the surface cleaning head <b>102</b>. For example, the first agitator <b>114</b> (or the second agitator <b>116</b>) can be configured to move in response to changes in the surface to be cleaned <b>124</b> such that the first agitator extension distance <b>130</b> (or second agitator extension distance <b>132</b>) changes.

0022As shown, the surface cleaning head <b>102</b> includes a drive system <b>136</b> configured to cause the first and second agitators <b>114</b> and <b>116</b> to rotate concurrently. The drive system <b>136</b> is configured to couple the first agitator <b>114</b> to the second agitator <b>116</b> such that a rotation of the first agitator <b>114</b> causes a corresponding rotation of the second agitator <b>116</b>. The drive system <b>136</b> can be configured such that the first and second agitators <b>114</b> and <b>116</b> rotate at the same or different speeds. The drive system <b>136</b> can be further configured such that the first and second agitators <b>114</b> and <b>116</b> rotate in the same or different directions. For example, the drive system <b>136</b> can be configured such that the first and second agitators <b>114</b> and <b>116</b> are counter rotating such that dislodged debris is urged towards a central portion of the open end <b>122</b>. By way of further example, the drive system <b>136</b> can be configured such that the first and second agitator <b>114</b> and <b>116</b> rotate in the same (or a common) direction (e.g., such that debris is urged towards a rearward portion of the surface cleaning head <b>102</b>).

0023While <figref idref="DRAWINGS">FIG. <b>1</b></figref> generally illustrates an upright surface treatment apparatus having the drive system <b>136</b>. Other surface treatment apparatuses may utilize the drive system <b>136</b>. For example, robotic vacuum cleaners, canister vacuum cleaners, handheld vacuum cleaners, central vacuum cleaners, upright surface treatment apparatuses having a configurations different from that shown in <figref idref="DRAWINGS">FIG. <b>1</b></figref> (e.g., at least a portion of the vacuum assembly <b>106</b> may be included in the surface cleaning head <b>102</b>), and/or any other surface treatment apparatus. In instances where the vacuum assembly is included in the surface cleaning head <b>102</b>, the surface cleaning head <b>102</b> may be operated independent from the upright section <b>104</b>.

0024<figref idref="DRAWINGS">FIG. <b>2</b></figref> shows a schematic example of the drive system <b>136</b> of <figref idref="DRAWINGS">FIG. <b>1</b></figref>. As shown, the drive system <b>136</b> includes a first magnet ring <b>200</b> and a second magnet ring <b>202</b>. The first magnet ring <b>200</b> includes a first set of magnets <b>204</b> arranged in a ring shape and the second magnet ring <b>202</b> includes second set of magnets <b>206</b> arranged in a ring shape. The first magnet ring <b>200</b> defines a first ring inner perimeter <b>208</b> and a first ring outer perimeter <b>210</b>. The second magnet ring <b>202</b> defines a second ring inner perimeter <b>212</b> and a second ring outer perimeter <b>214</b>.

0025The first set of magnets <b>204</b> are arranged according to polarity. For example, the first set of magnets <b>204</b> may be arranged such that a polarity between immediately adjacent magnets alternates along the first ring inner perimeter <b>208</b> and the first ring outer perimeter <b>210</b>. In other words, the first ring inner perimeter <b>208</b> and the first ring outer perimeter <b>210</b> are defined by the north and south poles of the first set of magnets <b>204</b>, wherein each north pole is immediately adjacent a south pole of another magnet of the first set of magnets <b>204</b>. As such, the first ring inner perimeter <b>208</b> may generally be described as having a polarity that alternates along the first ring inner perimeter <b>208</b> and the first ring outer perimeter <b>210</b> may generally be described as having a polarity that alternates along the first ring outer perimeter <b>210</b>.

0026The second set of magnets <b>206</b> are also arranged according to polarity. For example, the second set of magnets <b>206</b> may be arranged such that a polarity between immediately adjacent magnets alternates along the second ring inner perimeter <b>212</b> and the second ring outer perimeter <b>214</b>. In other words, the second ring inner perimeter <b>212</b> and the second ring outer perimeter <b>214</b> are defined by the north and south poles of the second set of magnets <b>206</b>, wherein each north pole is immediately adjacent a south pole of another magnet of the second set of magnets <b>206</b>. As such, the second ring inner perimeter <b>212</b> may generally be described as having a polarity that alternates along the second ring inner perimeter <b>212</b> and the second ring outer perimeter <b>214</b> may generally be described as having a polarity that alternates along the second ring outer perimeter <b>214</b>.

0027As shown, the first magnet ring <b>200</b> may be oriented relative to the second magnet ring <b>202</b> such that magnetic fields of the first set of magnets <b>204</b> interact with magnetic fields of the second set of magnets <b>206</b>. For example, at a location where a separation distance <b>216</b> between the first ring outer perimeter <b>210</b> and the second ring outer perimeter <b>214</b> is minimized a polarity of the first ring outer perimeter <b>210</b> may be opposite the polarity of the second ring outer perimeter <b>214</b>. In other words, at the location where the separation distance <b>216</b> is minimized, one of a north pole or a south pole of a magnet of the first set of magnets <b>204</b> faces the other of a north pole or a south pole of a magnet of the second set of magnets <b>206</b>.

0028As such, the first magnet ring <b>200</b> may generally be described a first magnetic gear, wherein the magnetic fields generated by each of the magnets of the first set of magnets <b>204</b> may generally be described as defining the cogs (or teeth) of the first magnetic gear. Further, the second magnet ring <b>202</b> may generally be described as a second magnetic gear, wherein the magnetic fields generated by each of the magnets of the second set of magnets <b>206</b> may generally be described as defining the cogs (or teeth) of the second magnetic gear. In operation, the magnetic fields of the first and second magnetic gears interact such that a rotation in one magnetic gear causes a corresponding rotation in the other magnetic gear.

0029In some instances, the drive system <b>136</b> may include a temporary magnet <b>218</b> that may be positioned between the first and second magnet rings <b>200</b> and <b>202</b>. The temporary magnet <b>218</b> can be positioned between the first and second magnet rings <b>200</b> and <b>202</b> such that the temporary magnet <b>218</b> interacts with the magnetic fields generated by the first and second sets of magnets <b>204</b> and <b>206</b>. For example, the temporary magnet <b>218</b> may be positioned between the first and second magnet rings <b>200</b> and <b>202</b> proximate to the location where the separation distance <b>216</b> is minimized. By way of further example, a central axis (e.g., a central longitudinal axis) of the temporary magnet <b>218</b> may be spaced apart from the first ring outer perimeter <b>210</b> by a distance measuring half of the minimum separation distance <b>216</b> and may be spaced apart from the second ring outer perimeter <b>214</b> by a distance measuring half of the minimum separation distance <b>216</b>. The temporary magnet <b>218</b> may be configured to orient and/or control a direction of rotation of the first and second magnet rings <b>200</b> and <b>202</b>. For example, the temporary magnet <b>218</b> may cause the first and second magnet rings <b>200</b> and <b>202</b> to rotate in the same direction. The temporary magnet <b>218</b> may be an iron rod or pin that extends between the first and second magnet rings <b>200</b> and <b>202</b>.

0030<figref idref="DRAWINGS">FIG. <b>3</b></figref> shows a schematic example of the drive system <b>136</b> coupled to the first and second agitators <b>114</b> and <b>116</b>. As shown, the first set of magnets <b>204</b> of the first magnet ring <b>200</b> is coupled to the second agitator <b>116</b> and the second set of magnets <b>206</b> of the second magnet ring <b>202</b> is coupled to the first agitator <b>114</b>. As such, the first and second magnet rings <b>200</b> and <b>202</b> rotate together with the first and second agitators <b>114</b> and <b>116</b>. For example, when an agitator drive motor <b>300</b> causes the first agitator <b>114</b> to rotate, the second magnet ring <b>202</b> rotates with the first agitator <b>114</b>. Rotation of the second magnet ring <b>202</b> causes a corresponding rotation in the first magnet ring <b>200</b> as a result of the interaction between the magnet fields of the first and second sets of magnets <b>204</b> and <b>206</b>. A rotation of the first magnet ring <b>200</b> causes a corresponding rotation in the second agitator <b>116</b>. As such, the drive system <b>136</b> can generally be described as being configured to transfer a rotational motion of the first agitator <b>114</b> to the second agitator <b>116</b> through the use of one or more magnetic gears.

0031In some instances, the agitator drive motor <b>300</b> may be included within the first agitator <b>114</b> and configured to cause the first agitator <b>114</b> to rotate. In other instances, the agitator drive motor <b>300</b> may be external to the first agitator <b>114</b> and configured to cause the first agitator <b>114</b> to rotate. For example, the agitator drive motor <b>300</b> may be configured to cause the first agitator <b>114</b> to rotate using one or more belts and/or traditional gears (gears relying on physical inter-engagement). By way of further example, the agitator drive motor <b>300</b> may be configured to cause the first agitator <b>114</b> to rotate using one or more magnetic gears.

0032<figref idref="DRAWINGS">FIG. <b>4</b></figref> shows a perspective view of a surface cleaning head <b>400</b>, which may be an example of the surface cleaning head <b>102</b> of <figref idref="DRAWINGS">FIG. <b>1</b></figref>, and <figref idref="DRAWINGS">FIG. <b>5</b></figref> shows a top view of the surface cleaning head <b>400</b>. As shown, the surface cleaning head <b>400</b> includes a body <b>402</b>, one or more wheels <b>404</b> rotatably coupled to the body <b>402</b>, an agitator chamber <b>406</b> that defines a cavity <b>408</b> having an open end <b>410</b>, the cavity <b>408</b> being defined within the body <b>402</b>, a first and second agitator <b>412</b> and <b>414</b> are rotatably coupled to the body <b>402</b> and extend within the agitator chamber <b>406</b> such that at least a portion of the first and second agitators <b>412</b> and <b>414</b> protrude from the open end <b>410</b> in a direction away from the agitator chamber <b>406</b> (e.g., towards a surface to be cleaned such as a floor). In some instances, the second agitator <b>414</b> may extend from the cavity <b>408</b> such that the second agitator <b>414</b> defines a forward most portion of the surface cleaning head <b>400</b>. The surface cleaning head <b>400</b> may further include a fluid pathway <b>418</b> that is fluidly coupled to the agitator chamber <b>406</b>. In operation, a suction motor (e.g., the suction motor <b>108</b> of <figref idref="DRAWINGS">FIG. <b>1</b></figref>) is configured to cause air to be drawn from the agitator chamber <b>406</b> and into the fluid pathway <b>418</b>. As shown, the surface cleaning head <b>400</b> may include a plurality of wheels <b>404</b> and a plurality of fluid pathways <b>418</b>, wherein a respective fluid pathway <b>418</b> extends through a respective wheel <b>404</b>. As such, in some instances, the plurality of wheels <b>404</b> can be configured to be rotatably coupled to a respective fluid pathway <b>418</b>.

0033The first and second agitators <b>412</b> and <b>414</b> are configured to rotate together at the same or different speeds and in the same or different directions. As shown, the first agitator <b>412</b> includes a motor chamber <b>420</b>. An agitator motor <b>422</b> is disposed within the motor chamber <b>420</b> and configured to cause the first agitator <b>412</b> to rotate. The agitator motor <b>422</b> may have, for example, a power rating in a range of 75 watts (W) to 125 W. By way of further example, the agitator motor <b>422</b> may have a power rating of 100 W.

0034The rotational movement of the first agitator <b>412</b> may be transferred to the second agitator <b>414</b> using a drive system <b>424</b> (which may be an example of the drive system <b>136</b> of <figref idref="DRAWINGS">FIG. <b>1</b></figref>). The drive system <b>424</b> may include at least two magnetic gears configured to cooperate to cause the second agitator <b>414</b> to rotate concurrently with the first agitator <b>412</b>.

0035The first and second agitators <b>412</b> and <b>414</b> may include one or more cleaning elements <b>426</b> and <b>428</b> (e.g., bristles, such as nylon or carbon bristles, continuous flexible strips, such as rubber or fabric flaps, and/or any other cleaning element). The cleaning elements <b>426</b> and <b>428</b> may be arranged around the first and second agitators <b>412</b> and <b>414</b> according to the same or different pattern. For example, the cleaning elements <b>426</b> of the first agitator <b>412</b> may be arranged according to a spiral pattern and the cleaning elements <b>428</b> of the second agitator <b>414</b> may be arranged in a filled pattern (e.g., a core of the second agitator <b>414</b> is substantially obscured by the cleaning elements <b>428</b>).

0036The cleaning elements <b>426</b> of the first agitator <b>412</b> may be the same or different from the cleaning elements <b>428</b> of the second agitator <b>414</b>. In some instances, the cleaning elements <b>426</b> and <b>428</b> may have a shape and/or material that encourages a specific cleaning behavior (e.g., hair migration, improved hard/soft floor cleaning, and/or any other cleaning behavior). For example, the cleaning elements <b>428</b> of the second agitator <b>414</b> may be softer (e.g., more flexible) than the cleaning elements <b>426</b> of the first agitator <b>412</b>.

0037In some instances, the first agitator <b>412</b> may include at least two different cleaning elements <b>426</b>. For example, a first cleaning element <b>426</b> may be stiffer than a second cleaning element <b>426</b>. In this example, the first cleaning element <b>426</b> may be, for example, nylon or carbon bristles having a diameter of 0.23 millimeters (mm)+/−0.02 mm and the second element <b>426</b> may be softer bristles (e.g., having a diameter of less than 0.23 mm) or flexible strips of a continuous material. By way of further example, the first cleaning element <b>426</b> may be a first flexible strip (e.g., of bristles or a continuous material) arranged around the first agitator <b>412</b> according to a spiral pattern and the second cleaning element <b>426</b> may be a second flexible strip arranged around the first agitator <b>412</b> according to a spiral pattern, wherein the second flexible strip has a rigidity that is different from that of the first flexible strip. In some instances, the dimensions of the first flexible strip (e.g., a width or height) may be different from the dimension of the second flexible strip. For example, when the first flexible strip is wider than the second flexible strip, the first flexible strip may be configured to be less rigid than the second flexible strip.

0038Similarly, the second agitator <b>414</b> may include at least two different cleaning elements <b>428</b>. For example, a first cleaning element <b>428</b> may be stiffer than a second cleaning element <b>428</b>. In this example, the first cleaning element <b>428</b> may be, for example, nylon or carbon bristles having a diameter of 0.23 millimeters (mm)+/−0.02 mm and the second element <b>428</b> may be softer bristles (e.g., having a diameter of less than 0.23 mm) or flexible strips of a continuous material. By way of further example, the first cleaning element <b>428</b> may be a first flexible strip (e.g., of bristles or a continuous material) arranged around the second agitator <b>414</b> according to a spiral pattern and the second cleaning element <b>428</b> may be a second flexible strip arranged around the second agitator <b>414</b> according to a spiral pattern, wherein the second flexible strip has a rigidity that is different from that of the first flexible strip. In some instances, the dimensions of the first flexible strip (e.g., a width or height) may be different from the dimension of the second flexible strip. For example, when the first flexible strip is wider than the second flexible strip, the first flexible strip may be less rigid than the second flexible strip.

0039As shown, the first agitator <b>412</b> includes a bar <b>430</b> that extends through the motor chamber <b>420</b>. The bar <b>430</b> can be configured to couple to the body <b>402</b> of the surface cleaning head <b>400</b>. For example, the bar <b>430</b> can be coupled to the body <b>402</b> such that the first agitator <b>412</b> is cantilevered within the agitator chamber <b>406</b>. Cantilevering the first agitator <b>412</b> within the agitator chamber <b>406</b> may result in a gap <b>432</b> being formed between a distal end of the first agitator <b>412</b> and a sidewall <b>434</b> of the agitator chamber <b>406</b> that extends transverse to the first agitator <b>412</b>. The first agitator <b>412</b> can be configured such that, in operation, fibrous debris (e.g., hair or string) is migrated along the first agitator <b>412</b> towards the gap <b>432</b>. Upon reaching the gap <b>432</b>, the fibrous debris may fall off the first agitator <b>412</b> and become entrained within air flowing through the surface cleaning head <b>400</b>.

0040<figref idref="DRAWINGS">FIG. <b>6</b></figref> shows a side view of the surface cleaning head <b>400</b> of <figref idref="DRAWINGS">FIG. <b>4</b></figref>. The first agitator <b>412</b> can be configured to float relative to the body <b>402</b>. In other words, the first agitator <b>412</b> may be configured to move along one or more axes (e.g., a vertical and/or horizontal axis). For example, the first agitator <b>412</b> may be configured to move along an axis <b>600</b> (e.g., an axis having both vertical and horizontal components). In some instances, movement of the first agitator <b>412</b> along one or more axes may be caused by variations in a surface to be cleaned (e.g., a presence of a threshold extending between two different surface types such as hard floor and carpet). The first agitator <b>412</b> can be biased such that it is urged in a direction of the surface to be cleaned such that a consistent engagement between the first agitator <b>412</b> and the surface to be cleaned can be maintained. Additionally, or alternatively, the first agitator <b>412</b> can be configured to move towards or away from a surface to be cleaned based, at least in part, on a surface type (e.g., carpet or hard floor). For example, the first agitator <b>412</b> can be configured to be moved away from a hardwood floor (e.g., to prevent damage, such as scratches, to the hardwood floor caused by cleaning elements of the first agitator <b>412</b>) and to be moved toward a carpet (e.g., to increase engagement between the cleaning elements of the first agitator <b>412</b> and the carpet).

0041The second agitator <b>414</b> may additionally, or alternatively, be configured to float relative to the body <b>402</b> in a manner similar to that of the first agitator <b>412</b>. As such, at least one of the first and/or second agitators <b>412</b> and/or <b>414</b> may be configured to float relative to the body. Additionally, or alternatively, the second agitator <b>414</b> may be configured to move towards or away from a surface to be cleaned based, at least in part, on surface type in a manner similar to that of the first agitator <b>412</b>. As such, at least one of the first and/or second agitators <b>412</b> and/or <b>414</b> may be configured to move towards or away from a surface to be cleaned based, at least in part, on surface type.

0042In some instances, one or more of the first and/or second agitators <b>412</b> and/or <b>414</b> can be configured to move towards and away from the surface to be cleaned independently of each other. For example, the first agitator <b>412</b> can be configured to float relative to the body <b>402</b> independent of the second agitator <b>414</b>. In some instances, the movement of the first agitator <b>412</b> (or second agitator <b>414</b>) relative to the second agitator <b>414</b> (or first agitator <b>412</b>) may be configured such that the magnetic gears of the drive system <b>424</b> continue to cooperate to transfer rotational motion from the first agitator <b>412</b> to the second agitator <b>414</b>. For example, the first agitator <b>412</b> may be configured to move along a path configured to maintain an orientation between magnetic gears of the drive system <b>424</b> that allows the transfer of rotational motion from the first agitator <b>412</b> to the second agitator <b>414</b>. In other words, the drive system <b>424</b> allows for a plurality of agitators (e.g., the first and second agitators <b>412</b> and <b>414</b>) to be driven by a single agitator drive motor (e.g., the agitator motor <b>422</b>) while still being able to move independently of each other based on variations in the surface to be cleaned.

0043<figref idref="DRAWINGS">FIG. <b>7</b></figref> shows a schematic bottom view of a robotic surface treatment apparatus <b>700</b>. As shown, the robotic surface treatment apparatus <b>700</b> includes at least one driven wheel <b>702</b> configured to urge the robotic surface treatment apparatus <b>700</b> across a surface to be cleaned, a first and second agitator <b>704</b> and <b>706</b> disposed within an agitator chamber <b>708</b>, a debris collector <b>710</b> fluidly coupled to the agitator chamber <b>708</b>, and a suction motor <b>712</b> fluidly coupled to the debris collector <b>710</b> and configured to urge air to flow into the agitator chamber <b>708</b>. The robotic surface treatment apparatus <b>700</b> may include one or more side brushes <b>714</b> configured to urge debris towards the first and second agitators <b>704</b> and <b>706</b>. The first agitator <b>704</b> may be coupled to an agitator motor <b>716</b> such that the agitator motor <b>716</b> causes the first agitator <b>704</b> to rotate. A drive system <b>718</b> (which may be an example of the drive system <b>136</b>) transfers rotational motion from the first agitator <b>704</b> to the second agitator <b>706</b> such that the first and second agitators <b>704</b> and <b>706</b> rotate concurrently. The drive system <b>718</b> includes a plurality of magnetic gears configured to cooperate to cause the first and second agitators <b>704</b> and <b>706</b> to rotate concurrently. The first and second agitators <b>704</b> and <b>706</b> may rotate at the same or different speeds and/or rotate in the same or different directions.

0044Use of magnetic gears in the drive system <b>718</b> may result in the drive system being more compact compared to a drive system using belts and/or traditional gears. This may maximize the space available within the robotic surface treatment apparatus <b>700</b> for other components (e.g., one or more batteries, motors, and/or any other component). In some instances, the drive system <b>718</b> may be configured to cause both the first and second agitators <b>704</b> and <b>706</b> to rotate in the same direction (e.g., through use of a temporary magnet disposed between at least two magnetic gears). For example, the first and second agitator <b>704</b> and <b>706</b> may be configured to rotate in a direction that corresponds to a rotational direction of the at least when driven wheel <b>702</b> when the robotic surface treatment apparatus <b>700</b> is moving in a forward direction. Such a configuration may result in the rotation of the first and second agitators <b>704</b> and <b>706</b> encouraging forward movement of the robotic surface treatment apparatus <b>700</b>, which may reduce an amount energy consumed by the at least one driven wheel <b>702</b>. In some instances, the first and/or second agitators <b>704</b> and/or <b>706</b> may be configured to move towards or away from a surface to be cleaned. For example, the first and/or second agitators <b>704</b> and/or <b>706</b> may be configured to float relative to a body <b>720</b> of the robotic surface treatment apparatus <b>700</b>.

0045An example of a surface treatment apparatus, consistent with the present disclosure, may include a first agitator, a second agitator, and a drive system configured to cause the second agitator to rotate concurrently with the first agitator, the drive system including at least a first magnetic gear and a second magnetic gear.

0046In some instances, the surface treatment apparatus may further include an agitator motor configured to cause the first agitator to rotate. In some instances, the drive system may be configured to cause the first and second agitator to rotate at different speeds. In some instances, the drive system may be configured to cause the first and second agitator to rotate in a common direction. In some instances, the surface treatment apparatus may further include a body, the first agitator and the second agitator being rotatably coupled to the body and at least one of the first agitator or the second agitator is configured to float relative to the body. In some instances, the first agitator may be configured to float relative to the body independent of the second agitator. In some instances, the drive system further may further include a temporary magnet disposed between the first magnetic gear and the second magnetic gear. In some instances, the temporary magnet may be an iron pin. In some instances, a diameter of the first agitator may measure differently from a diameter of the second agitator. In some instances, the first magnetic gear may be coupled to the first agitator and the second magnetic gear may be coupled to the second agitator.

0047Another example of a surface treatment apparatus, consistent with the present disclosure, may include an upright section and a surface treatment head. The upright section may be pivotally coupled to the surface treatment head. The surface treatment head may include a first agitator, a second agitator, and a drive system having a first magnetic gear coupled to the first agitator and a second magnetic gear coupled to the second agitator, a rotation of the first magnetic gear causing a corresponding rotation of the second magnetic gear.

0048In some instances, the surface treatment apparatus may further include an agitator motor configured to cause the first agitator to rotate. In some instances, the drive system may be configured to cause the first and second agitator to rotate at different speeds. In some instances, the drive system may be configured to cause the first and second agitator to rotate in a common direction. In some instances, the surface treatment apparatus may further include a body, the first agitator and the second agitator being rotatably coupled to the body and at least one of the first agitator or the second agitator is configured to float relative to the body. In some instances, the first agitator may be configured to float relative to the body independent of the second agitator. In some instances, the drive system may further include a temporary magnet disposed between the first magnetic gear and the second magnetic gear. In some instances, the temporary magnet may be an iron pin. In some instances, a diameter of the first agitator may measure differently from a diameter of the second agitator. In some instances, the first agitator may be cantilevered.

0049An example of a robotic surface treatment apparatus, consistent with the present disclosure, may include at least one driven wheel, a debris collector, a first agitator, a second agitator, and a drive system configured to cause the second agitator to rotate concurrently with the first agitator, the drive system including at least a first magnetic gear and a second magnetic gear.

0050In some instances, the robotic surface treatment apparatus may further include an agitator motor configured to cause the first agitator to rotate. In some instances, the drive system may be configured to cause the first and second agitator to rotate at different speeds. In some instances, the drive system may be configured to cause the first and second agitator to rotate in a common direction. In some instances, the robotic surface treatment apparatus may further include a body, the first agitator and the second agitator being rotatably coupled to the body and at least one of the first agitator or the second agitator is configured to float relative to the body. In some instances, the first agitator may be configured to float relative to the body independent of the second agitator. In some instances, the drive system further may further include a temporary magnet disposed between the first magnetic gear and the second magnetic gear. In some instances, the temporary magnet may be an iron pin. In some instances, a diameter of the first agitator may measure differently from a diameter of the second agitator. In some instances, the first magnetic gear may be coupled to the first agitator and the second magnetic gear may be coupled to the second agitator.

0051While the principles of the invention have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.